Instrument Carriage Assembly for Surgical System

ABSTRACT

A robotic assembly is configured to support, insert, retract, and actuate a surgical instrument mounted to the robotic assembly. The robotic assembly includes an instrument holder base member, a motor housing moveably mounted to the instrument holder base member, a carriage drive mechanism operable to translate the motor housing along the instrument holder base member, a plurality of drive motors, a plurality of gear boxes, and a plurality of output drive couplings driven by the gear boxes. The robotic assembly includes a sensor assembly that includes an orientation sensor, a sensor target, and a sensor shaft drivingly coupling the sensor target to a corresponding one of the output drive couplings.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a Divisional of U.S. Ser. No. 13/907,049filed May 31, 2013 (Allowed); which application claims the benefit ofU.S. Provisional Appln. No. 61/654,391 filed Jun. 1, 2012; the contents,each of which are incorporated herein by reference for all purposes.

BACKGROUND

Minimally invasive medical techniques are intended to reduce the amountof extraneous tissue that is damaged during diagnostic or surgicalprocedures, thereby reducing patient recovery time, discomfort, anddeleterious side effects. One effect of minimally invasive surgery, forexample, is reduced post-operative hospital recovery times. Because theaverage hospital stay for a standard surgery is typically significantlylonger than the average stay for an analogous minimally invasivesurgery, increased use of minimally invasive techniques could savemillions of dollars in hospital costs each year. While many of thesurgeries performed each year in the United States could potentially beperformed in a minimally invasive manner, only a portion of the currentsurgeries use these advantageous techniques due to limitations inminimally invasive surgical instruments and the additional surgicaltraining involved in mastering them.

Minimally invasive robotic surgical or telesurgical systems have beendeveloped to increase a surgeon's dexterity and avoid some of thelimitations on traditional minimally invasive techniques. Intelesurgery, the surgeon uses some form of remote control (e.g., aservomechanism or the like) to manipulate surgical instrument movements,rather than directly holding and moving the instruments by hand. Intelesurgery systems, the surgeon can be provided with an image of thesurgical site at a surgical workstation. While viewing a two or threedimensional image of the surgical site on a display, the surgeonperforms the surgical procedures on the patient by manipulating mastercontrol devices, which in turn control motion of the servo-mechanicallyoperated instruments.

The servomechanism used for telesurgery will often accept input from twomaster controllers (one for each of the surgeon's hands) and may includetwo or more robotic arms on each of which a surgical instrument ismounted. Operative communication between master controllers andassociated robotic arm and instrument assemblies is typically achievedthrough a control system. The control system typically includes at leastone processor that relays input commands from the master controllers tothe associated robotic arm and instrument assemblies and back from theinstrument and arm assemblies to the associated master controllers inthe case of, for example, force feedback or the like. One example of arobotic surgical system is the DA VINCI® system available from IntuitiveSurgical, Inc. of Sunnyvale, Calif.

A variety of structural arrangements can be used to support the surgicalinstrument at the surgical site during robotic surgery. The drivenlinkage or “slave” is often called a robotic surgical manipulator, andexemplary linkage arrangements for use as a robotic surgical manipulatorduring minimally invasive robotic surgery are described in U.S. Pat.Nos. 7,594,912; 6,758,843; 6,246,200; and 5,800,423; the fulldisclosures of which are incorporated herein by reference. Theselinkages often make use of a parallelogram arrangement to hold aninstrument having a shaft. Such a manipulator structure can constrainmovement of the instrument so that the instrument pivots about a remotecenter of manipulation positioned in space along the length of the rigidshaft. By aligning the remote center of manipulation with the incisionpoint to the internal surgical site (for example, with a trocar orcannula at an abdominal wall during laparoscopic surgery), an endeffector of the surgical instrument can be positioned safely by movingthe proximal end of the shaft using the manipulator linkage withoutimposing potentially dangerous forces against the abdominal wall.Alternative manipulator structures are described, for example, in U.S.Pat. Nos. 6,702,805; 6,676,669; 5,855,583; 5,808,665; 5,445,166; and5,184,601; the full disclosures of which are incorporated herein byreference.

A variety of structural arrangements can also be used to support andposition the robotic surgical manipulator and the surgical instrument atthe surgical site during robotic surgery. Supporting linkage mechanisms,sometimes referred to as set-up joints, or set-up joint arms, are oftenused to position and align each manipulator with the respective incisionpoint in a patient's body. The supporting linkage mechanism facilitatesthe alignment of a surgical manipulator with a desired surgical incisionpoint and targeted anatomy. Exemplary supporting linkage mechanisms aredescribed in U.S. Pat. Nos. 6,246,200 and 6,788,018, the fulldisclosures of which are incorporated herein by reference.

While the new telesurgical systems and devices have proven highlyeffective and advantageous, still further improvements are desirable. Ingeneral, improved minimally invasive robotic surgery systems aredesirable. It would be particularly beneficial if these improvedtechnologies enhanced the efficiency and ease of use of robotic surgicalsystems. For example, it would be particularly beneficial to increasemaneuverability, improve space utilization in an operating room, providea faster and easier set-up, inhibit collisions between robotic devicesduring use, and/or reduce the mechanical complexity and size of thesenew surgical systems.

BRIEF SUMMARY

The following presents a simplified summary of some embodiments of theinvention in order to provide a basic understanding of the invention.This summary is not an extensive overview of the invention. It is notintended to identify key/critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome embodiments of the invention in a simplified form as a prelude tothe more detailed description that is presented later.

Robotic assemblies are disclosed that support, insert, retract, andactuate a surgical instrument mounted to the robotic assembly. Therobotic assemblies include drive motors that are mounted in a commonmotor housing in a compact pattern. In many embodiments, the drivemotors include magnetic flux shields that inhibit interference betweenadjacent drive motors. As a result, the drive motors can beindependently driven to articulate a corresponding portion of thesurgical instrument without causing unintended articulation of otherportions of the surgical instrument. And in many embodiments, sensorassemblies are included that directly monitor the orientation of outputcouplers used to actuate the surgical instrument. As a result, theabsolute orientation of the output couplers can be readily determined—acapability that is useful when resetting a surgical system such as maybe required in certain circumstances, for example, after a powerfailure. Additionally, in many embodiments, the disclosed roboticassemblies provide high actuation power and unlimited actuation range ofmotion from compact assemblies, thereby enabling use with advancedsurgical instruments such as surgical staplers and vessel sealers.

Thus, in one aspect, a robotic assembly is disclosed that is configuredto support, insert, retract, and actuate a surgical instrument mountedto the robotic assembly. The robotic assembly includes an instrumentholder base member, a motor housing, a carriage drive mechanism, aplurality of drive motors, and a plurality of output drive couplings.The motor housing is moveably mounted to the instrument holder basemember. The carriage drive mechanism is operable to selectivelytranslate the motor housing relative to the instrument holder basemember along an insertion axis of the surgical instrument. Each of thedrive motors is mounted to the motor housing. One or more of the drivemotors includes a magnetic flux shield. Each of the output drivecouplings is drivingly coupled with a corresponding one of the drivemotors. Each of the output drive couplings is configured to drivinglycouple with a corresponding input drive coupling of the surgicalinstrument.

In many embodiments, the drive motors are configured to have high powerdensity. For example, in many embodiments, at least one of the drivemotors includes a brushless component motor having atrapezoidal-commutation motor constant (Km) greater than or equal to1.25 oz.-in/Wattŝ½, where Km=(Trapezoidal Commutation Torque Constant inoz.-in/Ampere/(square root of phase-to-phase winding resistance inOhms).

In many embodiments, one or more magnetic flux shields are configuredand placed to effectively contain magnetic flux to inhibit magneticinterference between motors and/or between motors and sensor assemblies.In many embodiments, a ferrous ring is used as a flux shield. In manyembodiments, one or more of the drive motors includes two magnetic fluxshields that are disposed at opposite ends of the drive motor. Each ofthe flux shields can include a ring made of a magnetically soft materialcontaining at least one of iron, cobalt, or nickel. In some embodiments,the flux shield can be a monolithic ferrous component providing the fluxshielding function of more than one motor. In some embodiments, two suchmonolithic flux shields are provided, one providing the shield functionfor one end of two or more motors (e.g., two, three, four, five, etc.)while the second shield component provides the shield function for theopposite end of the same two or more motors.

In many embodiments, the drive motors are positioned in close proximityto one or more adjacent drive motors. For example, in many embodiments,two or more of the drive motors are separated by less than fivemillimeters. And in many embodiments, two or more of the drive motorsare separated by less than two millimeters.

In many embodiments, there are at least five drive motors and each ofthe five drive motors is separated from at least two of the other drivemotors by less than five millimeters. And in many embodiments, each ofthe five drive motors is separated from at least two of the other drivemotors by less than two millimeters.

In another aspect, a robotic assembly is disclosed that is configured tosupport, insert, retract, and actuate a surgical instrument mounted tothe robotic assembly. The robotic assembly includes an instrument holderbase member, a motor housing, a carriage drive mechanism, a plurality ofdrive motors, a plurality of gear boxes, a plurality of output drivecouplings, and a sensor assembly. The motor housing is moveably mountedto the instrument holder base member. The carriage drive mechanism isoperable to selectively translate the motor housing relative to theinstrument holder base member along an insertion axis of the surgicalinstrument. Each of the drive motors is mounted to the motor housing.Each of the gear boxes is drivingly coupled with a one of the drivemotors. Each of the output drive couplings is drivingly coupled with acorresponding one of the gear boxes. Each of the output drive couplingsis configured to drivingly couple with a corresponding input drivecoupling of the surgical instrument. The sensor assembly includes anorientation sensor, a sensor target, and a sensor shaft. The sensorshaft drivingly couples the sensor target to a corresponding one of theoutput drive couplings through an aperture in an outer housing of thecorresponding gear box. The sensor shaft is driven by an output link ofthe corresponding gear box that rotates in unison with the correspondingoutput drive coupling. In many embodiments, the orientation sensoroptically reads the sensor target and reports the absolute rotationalposition to a control system.

In many embodiments, the robotic assembly includes a plurality of sensorassemblies. Each of the sensor assemblies includes an orientationsensor, a sensor target, and a sensor shaft. Each sensor shaft drivinglycouples the corresponding sensor target to a corresponding one of theoutput drive couplings through an aperture in an outer housing of thecorresponding gear box. Each sensor shaft is driven by an output link ofthe corresponding gear box that rotates in unison with the correspondingoutput drive coupling. In a preferred embodiment, the orientation sensorshaft is coupled to the output drive coupling with a gear ratio ofexactly 1:1.

In many embodiments, the gear boxes are compact and/or efficient. Forexample, the gear ratio between at least one of the motors and thecorresponding output drive coupling can be less than 40 to 1. And eachof the output gear boxes can have two or fewer gear reduction stages.

In many embodiments, the drive motors are disposed between theorientation sensors and the output drive couplings. In such embodiments,each of the sensor shafts can be drivingly coupled to the correspondingoutput drive coupling via a sensor shaft gear that extends through theaperture in the corresponding outer housing to engage an output gearthat rotates in unison with the corresponding output drive coupling. Inmany embodiments, two of the sensor shaft gears overlap along a shaftdirection parallel to rotation axes of the sensor shafts. One or more ofthe corresponding apertures and output gears can be configured toaccommodate the overlap of the sensor shaft gears along the shaftdirection.

In many embodiments, the gear boxes include a planetary gear box. Theplanetary gear box can include a shaft bearing configured to reactmoment so as to inhibit an axis of rotation of an inner race of theshaft bearing from becoming misaligned with an axis of rotation of anouter race of the shaft bearing. In many embodiments, the shaft bearingincludes two rows of rolling elements. In many embodiments, theplanetary gear box includes a carrier gear that has external teeth thatare engaged by a sensor shaft gear extending through the aperture. Thesensor shaft gear is drivingly coupled with the sensor shaft.

In another aspect, a robotic assembly is disclosed that is configured tosupport, insert, retract, and actuate a surgical instrument mounted tothe robotic assembly. The robotic assembly includes an instrument holderbase member, a motor housing, a carriage drive mechanism, five drivemotors, five gear boxes, five output drive couplings, and five sensorassemblies. The motor housing is moveably mounted to the instrumentholder base member. The carriage drive mechanism is operable toselectively translate the motor housing relative to the instrumentholder base member along an insertion axis of the surgical instrument.Each of the drive motors is mounted to the motor housing. Each of thegear boxes is drivingly coupled with a one of the drive motors. Each ofthe output drive couplings is drivingly coupled with a corresponding oneof the gear boxes. Each of the output drive couplings is configured todrivingly couple with a corresponding input drive coupling of thesurgical instrument. In some embodiments, this driving function isprovided through an intermediate mechanical sterile adapter couplingdevice, which provides separation of the non-sterile drive coupling fromthe sterile surgical instrument. Each sensor assembly includes anorientation sensor and a sensor shaft. Each sensor shaft drivinglycouples the orientation sensor to a corresponding one of the outputdrive couplings through an aperture in an outer housing of thecorresponding gear box. Each sensor shaft is driven by an output link ofthe corresponding gear box that rotates in unison with the correspondingoutput drive coupling.

In many embodiments, one or more of the axes of the output drivecouplings are parallel. For example, one or more of the axes of theoutput drive couplings can be substantially parallel with the insertionaxis.

In many embodiments, the output drive couplings are arranged in aparticular manner. For example, in many embodiments, the output drivecouplings are arranged in a pattern with four corner output drivecouplings and a central output drive coupling disposed between the fourcorner output drive couplings. In many embodiments, a maximum of twooutput drive couplings are stacked in a width direction of the motorhousing.

In many embodiments, the robotic assembly includes a radio frequencyidentification (RFID) antenna module. The RFID antenna module can beconfigured to read an instrument RFID tag at any suitable range, forexample, at a close range such as between 0 mm and approximately 20 mmseparation distance.

In many embodiments, the robotic assembly includes a circuit board thatincludes the five orientation sensors of the five sensor assemblies. Inmany embodiments, the circuit board further includes five rotororientation sensors where each of the rotor orientation sensors isconfigured to monitor the absolute angular orientation of a rotor of acorresponding one of the five drive motors.

The robotic assembly can be configured to drive a two-finger surgicalinstrument. For example, each of two of the output drive couplings thatare furthest away from the insertion axis can be used to actuate acorresponding finger of a two-finger surgical instrument. The relativemotions of the two fingers combine to provide both grip and yaw motionsof a surgical end effector of the two-finger surgical instrument.

For a fuller understanding of the nature and advantages of the presentinvention, reference should be made to the ensuing detailed descriptionand accompanying drawings. Other aspects, objects and advantages of theinvention will be apparent from the drawings and detailed descriptionthat follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a minimally invasive robotic surgery systembeing used to perform a surgery, in accordance with many embodiments.

FIG. 2 is a perspective view of a surgeon's control console for arobotic surgery system, in accordance with many embodiments.

FIG. 3 is a perspective view of a robotic surgery system electronicscart, in accordance with many embodiments.

FIG. 4 diagrammatically illustrates a robotic surgery system, inaccordance with many embodiments.

FIG. 5A is a partial view of a patient side cart (surgical robot) of arobotic surgery system, in accordance with many embodiments.

FIG. 5B is a front view of a robotic surgery tool, in accordance withmany embodiments.

FIG. 6 shows a robotic assembly, in accordance with many embodiments,that includes a carriage assembly slideably mounted to an instrumentholder base member for selective translation along an insertion axis ofa surgical instrument mounted to the carriage assembly.

FIG. 7 shows the robotic assembly of FIG. 6 with the carriage assemblyshown decoupled from the instrument holder base member.

FIG. 8 through FIG. 18 is a sequence of figures that illustratecomponents of the carriage assembly of FIG. 6.

FIG. 8 shows the as installed arrangement of drive motors of thecarriage assembly of FIG. 6.

FIG. 9 shows planetary gear boxes attached to the drive motors of FIG.8.

FIG. 10 shows sensor shafts coupled to output gears of the planetarygear boxes of FIG. 9.

FIG. 11 shows a motor housing supporting the components of FIG. 10.

FIG. 12 is an exploded view illustrating a resolver assembly thatmonitors the rotational orientation of the drive motors of the carriageassembly of FIG. 6.

FIG. 13 shows the installed resolver assembly of FIG. 12.

FIG. 14 is an exploded view illustrating an orientation sensor assemblythat monitors the rotational orientation of the sensor shafts of FIG.10.

FIG. 15 shows the installed orientation sensor assembly of FIG. 14.

FIG. 16 shows an electronic control assembly, a radio frequencyidentification (RFID) antenna, and a contact assembly for the carriageassembly of FIG. 6.

FIG. 17 and FIG. 18 show outer housing components of the carriageassembly of FIG. 6.

FIG. 19 shows one of the planetary gear boxes of FIG. 9.

FIG. 20 shows a cross-section of the planetary gear box of FIG. 19.

FIG. 21 shows one of the drive motors of FIG. 8.

FIG. 22 is an exploded view of the drive motor of FIG. 21 andillustrates ferrous end rings that serve as magnetic flux shields.

FIG. 23 shows a cross-section of the drive motor of FIG. 21.

FIG. 24 shows a robotic assembly, in accordance with many embodiments,that includes a carriage assembly slideably mounted to an instrumentholder base member for selective translation along an insertion axis ofa surgical instrument mounted to the carriage assembly.

FIG. 25 shows a drive assembly of the carriage assembly of FIG. 24.

DETAILED DESCRIPTION

In the following description, various embodiments of the presentinvention will be described. For purposes of explanation, specificconfigurations and details are set forth in order to provide a thoroughunderstanding of the embodiments. However, it will also be apparent toone skilled in the art that the present invention may be practicedwithout the specific details. Furthermore, well-known features may beomitted or simplified in order not to obscure the embodiment beingdescribed.

Minimally Invasive Robotic Surgery

Referring now to the drawings, in which like reference numeralsrepresent like parts throughout the several views, FIG. 1 is a plan viewillustration of a Minimally Invasive Robotic Surgical (MIRS) system 10,typically used for performing a minimally invasive diagnostic orsurgical procedure on a Patient 12 who is lying down on an Operatingtable 14. The system can include a Surgeon's Console 16 for use by aSurgeon 18 during the procedure. One or more Assistants 20 may alsoparticipate in the procedure. The MIRS system 10 can further include aPatient Side Cart 22 (surgical robot) and an Electronics Cart 24. ThePatient Side Cart 22 can manipulate at least one removably coupled toolassembly 26 (hereinafter simply referred to as a “tool”) through aminimally invasive incision in the body of the Patient 12 while theSurgeon 18 views the surgical site through the Console 16. An image ofthe surgical site can be obtained by an endoscope 28, such as astereoscopic endoscope, which can be manipulated by the Patient SideCart 22 to orient the endoscope 28. The Electronics Cart 24 can be usedto process the images of the surgical site for subsequent display to theSurgeon 18 through the Surgeon's Console 16. The number of surgicaltools 26 used at one time will generally depend on the diagnostic orsurgical procedure and the space constraints within the operating roomamong other factors. If it is necessary to change one or more of thetools 26 being used during a procedure, an Assistant 20 may remove thetool 26 from the Patient Side Cart 22, and replace it with another tool26 from a tray 30 in the operating room.

FIG. 2 is a perspective view of the Surgeon's Console 16. The Surgeon'sConsole 16 includes a left eye display 32 and a right eye display 34 forpresenting the Surgeon 18 with a coordinated stereo view of the surgicalsite that enables depth perception. The Console 16 further includes oneor more input control devices 36, which in turn cause the Patient SideCart 22 (shown in FIG. 1) to manipulate one or more tools. The inputcontrol devices 36 can provide the same degrees of freedom as theirassociated tools 26 (shown in FIG. 1) to provide the Surgeon withtelepresence, or the perception that the input control devices 36 areintegral with the tools 26 so that the Surgeon has a strong sense ofdirectly controlling the tools 26. To this end, position, force, andtactile feedback sensors (not shown) may be employed to transmitposition, force, and tactile sensations from the tools 26 back to theSurgeon's hands through the input control devices 36.

The Surgeon's Console 16 is usually located in the same room as thepatient so that the Surgeon may directly monitor the procedure, bephysically present if necessary, and speak to an Assistant directlyrather than over the telephone or other communication medium. However,the Surgeon can be located in a different room, a completely differentbuilding, or other remote location from the Patient allowing for remotesurgical procedures.

FIG. 3 is a perspective view of the Electronics Cart 24. The ElectronicsCart 24 can be coupled with the endoscope 28 and can include a processorto process captured images for subsequent display, such as to a Surgeonon the Surgeon's Console, or on another suitable display located locallyand/or remotely. For example, where a stereoscopic endoscope is used,the Electronics Cart 24 can process the captured images to present theSurgeon with coordinated stereo images of the surgical site. Suchcoordination can include alignment between the opposing images and caninclude adjusting the stereo working distance of the stereoscopicendoscope. As another example, image processing can include the use ofpreviously determined camera calibration parameters to compensate forimaging errors of the image capture device, such as optical aberrations.

FIG. 4 diagrammatically illustrates a robotic surgery system 50 (such asMIRS system 10 of FIG. 1). As discussed above, a Surgeon's Console 52(such as Surgeon's Console 16 in FIG. 1) can be used by a Surgeon tocontrol a Patient Side Cart (Surgical Robot) 54 (such as Patent SideCart 22 in FIG. 1) during a minimally invasive procedure. The PatientSide Cart 54 can use an imaging device, such as a stereoscopicendoscope, to capture images of the procedure site and output thecaptured images to an Electronics Cart 56 (such as the Electronics Cart24 in FIG. 1). As discussed above, the Electronics Cart 56 can processthe captured images in a variety of ways prior to any subsequentdisplay. For example, the Electronics Cart 56 can overlay the capturedimages with a virtual control interface prior to displaying the combinedimages to the Surgeon via the Surgeon's Console 52. The Patient SideCart 54 can output the captured images for processing outside theElectronics Cart 56. For example, the Patient Side Cart 54 can outputthe captured images to a processor 58, which can be used to process thecaptured images. The images can also be processed by a combination theElectronics Cart 56 and the processor 58, which can be coupled togetherto process the captured images jointly, sequentially, and/orcombinations thereof. One or more separate displays 60 can also becoupled with the processor 58 and/or the Electronics Cart 56 for localand/or remote display of images, such as images of the procedure site,or other related images.

FIGS. 5A and 5B show a Patient Side Cart 22 and a surgical tool 62,respectively. The surgical tool 62 is an example of the surgical tools26. The Patient Side Cart 22 shown provides for the manipulation ofthree surgical tools 26 and an imaging device 28, such as a stereoscopicendoscope used for the capture of images of the site of the procedure.Manipulation is provided by robotic mechanisms having a number ofrobotic joints. The imaging device 28 and the surgical tools 26 can bepositioned and manipulated through incisions in the patient so that akinematic remote center is maintained at the incision to minimize thesize of the incision. Images of the surgical site can include images ofthe distal ends of the surgical tools 26 when they are positioned withinthe field-of-view of the imaging device 28.

Instrument Carriage Assemblies

FIG. 6 and FIG. 7 show a robotic assembly 70, in accordance with manyembodiments, that includes a carriage assembly 72 and an instrumentholder assembly 74. The instrument holder assembly 74 includes aninstrument holder base member 76 and a spar fitting 78 slideably mountedto the instrument holder base member 76. The carriage assembly 72 ismountable to the spar fitting 78. The instrument holder assembly 74includes a carriage drive mechanism (not shown) that is operable toselectively translate the spar fitting 78 along the instrument holderbase member 76, thereby translating the carriage assembly 72 along theinstrument holder base member 76 along an insertion axis of a surgicalinstrument (not shown) mounted to the carriage assembly 72.

The carriage assembly 72 includes five output drive couplings 80. Eachof the output drive couplings 80 is configured to drivingly couple witha corresponding input drive coupling of a surgical instrument when thesurgical instrument is mounted to the carriage assembly 72. Each of thefive output drive couplings 80 can be independently actuated to actuatea corresponding mechanism of a mounted surgical instrument. For example,one of the output drive couplings 80 can be used to rotate an elongatedshaft of the surgical instrument, one can be used to articulate an endeffector of the mounted surgical instrument around a first axis (e.g.,pitch axis), one can be used to articulate the end effector around asecond axis (e.g., yaw axis) that is perpendicular to the first axis,one can be used to articulate a clamping jaw of the end effector, andone can be used to articulate a stapling and cutting cartridge of theend effector. In a preferred embodiment, the rotation axis of each ofthe five output drive couplings is substantially parallel to theelongate shaft of the surgical instrument. While the carriage assembly72 includes five output drive couplings 80, a carriage assembly can beconfigured with any suitable number of output drive couplings.

In many embodiments, two of the output drive couplings can be configuredto each drive a single finger of a two-finger surgical instrument. Therelative motions of the two fingers combine to provide both grip and yawmotions of the surgical end effector. In many embodiments, the twooutput drive couplings furthest from the surgical instrument shaft areused to drive these grip/yaw motions.

Also in a preferred embodiment, the output drive couplings are arrangedin an array so as to minimize the width of the carriage. For example, amaximum of two output drive couplings can be located adjacent to oneanother in a width direction of the carriage (see, for example, thearrangement of the drive couplings 80 in FIG. 6 where the two drivecouplings at the right side of the array of five drive couplings 80relative to the orientation of FIG. 6 are adjacent to one another in thewidth direction of the carriage and likewise the two drive couplings atthe left side of the array five drive couplings 80 relative to theorientation of FIG. 6 are adjacent to one another in the width directionof the carriage).

The carriage assembly 72 also includes a radio frequency identification(RFID) antenna module 82 and a contact assembly 84. The RFID antennamodule 82 can be used to interrogate an RFID tag on the surgicalinstrument or sterile adapter component, for example, to identify amounted surgical instrument and/or to detect the presence of a mountedsurgical instrument. The contact assembly 84 can connect to anidentification chip of a mounted surgical instrument, for example, toidentify a mounted surgical instrument and/or to detect the presence ofa mounted surgical instrument or sterile adapter. In a preferredembodiment, the RFID antenna module 82 is designed to read theinstrument RFID tag at close range, for example, between 0 mm andapproximately 20 mm separation distance. The RFID tag signal can then beused as one (redundant) piece of information to help determine theapproach, presence, and/or removal of the instrument from the carriage.

FIG. 8 shows the installed arrangement of drive motors 86 used toactuate the output drive couplings 80. In many embodiments, the drivemotors 86 are electronically commutated motors (ECMs), which arecontrolled by associated electronic commutation systems. An ECM haspermanent magnets that rotate and a fixed armature thereby eliminatingthe need to connect current to a moving armature. An electroniccontroller replaces the brush/commutator assembly of a brushed directcurrent (DC) motor. The orientation of the rotor for each of the drivemotors 86 is monitored by a sensor assembly and supplied to anelectronic controller for the drive motor. The drive motor orientationis used by the electronic controller to control the phase of thewindings of the drive motor to control rotation of the drive motor. Thedrive motors 86 are arranged in a pattern with four corner drive motorsand a central drive motor disposed between the four corner drive motors.In the illustrated arrangement, each of the four corner drive motors isdisposed immediately adjacent to (e.g., separated by less than fivemillimeters, separated by less than two millimeters) an adjacent cornerdrive motor and the central drive motor. And the central drive motor isdisposed immediately adjacent to each of the four corner drive motors.The arrangement provides open spaces on opposite sides of the centraldrive motor between two of the corner drive motors. In a preferredembodiment, the drive motors are a “component set” where the stator androtor are individual components, forming a complete and functional motoronly after being installed in the carriage housing.

FIG. 9 shows output assemblies 88, 90 coupled to the drive motors 86.Each of four of the output assemblies (output assemblies 88) includes aspring-loaded output drive coupling 80 and a two-stage planetary gearbox 92. The output assembly 90 includes a spring-loaded output drivecoupling 80 and a single-stage planetary gear box 94. Each of theplanetary gear boxes 92, 94 drivingly couple one of the spring-loadedoutput drive couplings 80 to a corresponding one of the drive motors 86.In many embodiments, the gear ratio of the output assembly gearbox ispreferably less than 40:1 in order to provide high efficiencyback-drivability. High efficiency back-drivability is an importantfeature enabling high performance surgical motions. In a preferredembodiment, each of the two-stage planetary gear boxes 92 provides anapproximately 28 to 1 gear reduction. The single-stage planetary gearbox 94 provides an approximately 5.3 to 1 gear reduction. Each of theplanetary gear boxes 92, 94 includes an outer housing that has a slottedaperture 96 (most of which are hidden relative to the view direction ofFIG. 9) that is aligned with a carrier gear having external gear teethconfigured to drive pinion gears that extend through the slottedaperture 96. Each of the externally-geared carrier gears are outputlinks for the planetary-gear boxes 92, 94 and therefore rotate in unisonwith the corresponding output drive coupling 80.

FIG. 10 shows five sensor assemblies 98 drivingly coupled to theexternally-geared carrier gears of the planetary-gear boxes 92, 94. Eachof the sensor assemblies 98 includes a pinion gear 100, a shaft assembly102 coupled to the pinion gear 100, and a sensor target 104, theorientation of which is monitored by an absolute orientation sensorassembly (not shown). Each pinion gear 100 extends through one of theslotted apertures 96 to engage and be driven by the externally-gearedcarrier gear of the corresponding planetary gear box. The five drivemotors 86 and associated planetary-gear boxes 92, 94 are arranged in apattern that provides two open volumes 106, 108, which are located onopposite sides of the central drive motor. Each of the planetary gearboxes 92, 94 is oriented such that its slotted aperture 96 faces one ofthe open volumes 106, 108. Two of the sensor assemblies 98 are disposedin the near-side open volume 106. And three of the sensor assemblies 98are disposed in the far-side open volume 108. The pinion gears 100 forthe sensor assemblies 98 that engage the corner planetary gear boxes arelocated in the same geometric plane as shown for the two pinion gears100 in the near-side open volume 106. The pinion gear 100 for the sensorassembly 98 that engages the central planetary gear box is disposedoffset from and overlaps the other two pinion gears disposed in thefar-side open volume 108. In many embodiments, the slotted apertures 96have an increased width to accommodate the possible positions of thepinion gear 100 associated with the overlap between the pinion gears 100disposed in the far-side open volume 108. Likewise, in many embodiments,the gear teeth of the externally-geared carrier gears have an increasedwidth to accommodate the possible positions of the pinion gear 100associated with the overlap between the pinion gears 100 disposed in thefar-side open volume 108.

Each shaft assembly includes a drive shaft 110, a bottom end bearing112, a top end bearing 114, and a compression spring 116. The top endbearing 114 can be translated along the drive shaft 110 therebycompressing the compression spring 116 to position the top end bearing114 for lateral installation of the sensor assembly 98 into a motorhousing (shown in FIG. 11). Once installed into the motor housing,extension of the compression spring 116 repositions the top end bearing114 into engagement with a corresponding bearing receptacle in the motorhousing.

FIG. 11 shows the motor housing 118 with the drive motors 86, planetarygear boxes 92, 94, and the sensor assemblies 98 mounted to the motorhousing 118. In many embodiments, the motor housing 118 is amonolithically machined component configured to accommodate and/orsupport the drive motors 86, the sensor assemblies 98, as well as othercomponents of the carriage assembly 72. In a preferred embodiment, themonolithically machined motor housing 118 is made from a material havingthermal conductivity greater than 70 W/m-K (e.g., magnesium oraluminum).

FIG. 12 is an exploded view showing a Hall-effect sensor assembly 120that includes a mounting frame 122 and five Hall-effect sensors 124mounted to the mounting frame 122. Each of the Hall-effect sensors 124monitors the orientation of a rotor of the corresponding drive motor 86by providing an output signal, which changes as the alternating Northand South magnetic poles of the motor rotor pass by the sensor. Anoutput signal from each of the Hall-effect sensors 124 is input to anelectronic controller for the corresponding drive motor. Each of theelectronic controllers uses the orientation signal to control the phaseof the windings of the corresponding drive motor to control rotation ofthe drive motor. The mounting frame 122 also includes receptacles 126that receive and support the bottom end bearings 112 of the five sensorassemblies 98. FIG. 13 shows the Hall-effect assembly 120 mounted to themotor housing 118.

FIG. 14 is an exploded view showing an absolute orientation sensorassembly 128 that includes a mounting frame 130 and ten orientationsensors 132 mounted to the mounting frame. Five of the orientationsensors 132 monitors the orientation of a corresponding one of thesensor assemblies 98, thereby monitoring the orientation of thecorresponding output drive coupling 80. Additionally, five of theorientation sensors monitor the orientation of the rotor component ofthe drive motor. These five orientation sensors provide a second meansof motor rotation sensing in addition to the Hall-effect sensorassembly. In many embodiments, the orientation sensors 132 includeoptical sensors that sense the angular orientation of an opticallyreadable pattern on the sensor target 104 of the corresponding sensorassembly 98, thereby sensing the orientation of the sensor target 104.FIG. 15 shows the orientation sensor assembly 128 mounted in itsinstalled position.

FIG. 16 through FIG. 18 show additional components of the carriageassembly 72. FIG. 16 shows the mounted positions of an electroniccontrol assembly 134, the radio frequency identification (RFID) antennamodule 82, and the contact assembly 84. FIG. 17 shows the mountedpositions of a lower housing 136 and a side cover 138. And FIG. 18 showsthe mounted positions of an outer housing 140.

FIG. 19 shows one of the two-stage planetary gear boxes 92 and anassociated one of the output drive couplings 80. The output drivecoupling 80 includes oppositely disposed drive receptacles 142, 144 thatreceive and drivingly coupled with corresponding drive extensionfeatures in a mating coupling. The drive receptacles 142, 144 aredisposed at different radial positions, thereby ensuring only onepossible angular orientation of engagement between the output drivecoupling 80 and the corresponding mating coupling.

FIG. 20 shows a cross-section of one of the two-stage planetary gearboxes 92. The planetary gear box 92 includes an outer housing 146, afirst planetary stage 148, a second planetary stage 150, a double-rowbearing 152. The first planetary stage 148 includes first stage planetgears 154 that interface with and are driven by a sun gear (not shown)mounted to the rotor of the corresponding drive motor 86. The firststage planet gears 154 are rotationally mounted to a first stage carrier156 that is fixedly attached to a first stage output sun gear 158. Thefirst stage planet gears 154 interface with an internal ring gear 160integral to the outer housing 146. The second planetary stage 150includes second stage planet gears 161 that interface with and aredriven by the first stage output sun gear 158. The second stage planetgears 161 are rotationally mounted to a second stage carrier 162. Thesecond stage planet gears 161 interface with the internal ring gear 160integral to the outer housing 146. The second stage carrier 162 hasexternal gear teeth 164 that interface with and drive the pinion gear100 of the corresponding sensor assembly 98. The second stage carrierexternal gear teeth 164 and the aperture 96 in the outer housing 146have a width in an axial direction of the planetary gear box 92 sized toaccommodate different possible positions of the corresponding piniongear 100 associated with the overlap of the pinion gears 100 asdescribed herein.

The second stage carrier 162 is fixedly coupled to an inner hollow shaft166 that interfaces with and is supported by an inner race of the doublerow bearing 152. A retainer ring 168 interfaces with a slot in the innerhollow shaft 166 and retains the assembly of the second stage carrier162 and the inner hollow shaft 166 relative to the inner race of thedouble row bearing 152. The double row bearing 152 includes two rows ofrolling elements, which serve to constrain the second stage carrier 162to rotate concentric to the outer housing 146. With the additionalrotational constraint provided by the double row bearing 152, the doublerow bearing 152 is used in place of two or more separate bearings,thereby allowing the planetary gear box 92 to have a smaller lengthalong the axial direction of the planetary gear box 92 as compared to atraditional planetary gear box having two or more separate bearings.

The second stage carrier 162 is drivingly coupled with the output drivecoupling 80 via external splines. A compression spring 170 biases theoutput drive coupling 80 into an extended position. The second stagecarrier 162, the output drive coupling 80, and the compression spring170 are configured so that the output drive coupling 80 can be displacedtowards the planetary gear box 92 during an engagement process in whichthe output drive coupling 80 is rotated until oriented such that thedrive receptacles 142, 144 are properly aligned with corresponding driveextension features in a mating coupling. The single-stage planetary gearbox 94 is configured similar to the two-stage planetary gear box 92, butwithout the first planetary stage 148.

FIG. 21 shows a side view of one of the drive motors 86. Each of thedrive motors 86 includes magnetic flux shields 172 disposed at oppositeends of the drive motor. FIG. 22 is an exploded view showing themagnetic flux shields 172 displaced from the rest of the drive motor 86.In many embodiments, each of the magnetic flux shields 172 is made froma suitable magnetically soft material (e.g., iron, cobalt, and/ornickel) having suitably high magnetic permeability. In the illustratedembodiment, each magnetic flux shield 172 is configured as a thin hollowcylinder having the illustrated axial length relative to the axiallength of the drive motor 86. The magnetic flux shields 172 are locatedat the ends of the drive motor 86 to entrain magnetic flux linesemanating from the magnetized motor rotor so that those magnetic fluxlines do not extend adjacent to the drive motor 86 to interfere with anadjacent drive motor and/or interfere with an adjacent motor sensor.

FIG. 23 shows a cross section of one of the drive motors 86. The drivemotor 86 includes a rotor 174 having permanent magnets 176, a top endbearing 178, a bottom end bearing 180, an output gear 182, anorientation sensor target 184 (note that this is the target for theoptical encoders shown in FIG. 14 and NOT the Hall-effect sensors shownin FIG. 12), an outer motor housing 186 in which motor windings 188 aredisposed, the magnetic flux shields 172, and an end cap 190. Each of themagnetic flux shields 172 is disposed at opposing ends of the drivemotor 86 so as to overlap a corresponding end of the motor windings 188.The location and the configuration of the magnetic flux shields 172 isselected to inhibit and/or prevent magnetic flux lines emanating fromthe magnetized motor rotor from interacting with an adjacent drivemotor(s) and/or with one or more adjacent motor orientation sensors. Theshields prevent the magnetic fields coming from the permanent magnets onthe rotor from interacting with adjacent motors and/or sensors. Themagnetic field coming from the stator windings is generally far weakerthan the rotating permanent magnet field of the rotor and is generallynot the main source of detrimental interference. The shields, however,do serve to attenuate both effects.

FIG. 24 shows a robotic assembly 200, in accordance with manyembodiments. The robotic assembly 200 includes an insertion axis base202, an insertion axis assembly 204, a carriage assembly 206, and asterile adapter 208. The insertion axis assembly 204 is telescopic andattached to the insertion axis base 202, which can be selectivelypositioned and oriented via an upstream linkage (not shown). Thecarriage assembly 206 is mounted to the insertion axis assembly 204 andis selectively translatable along the insertion axis assembly 204. Thecarriage assembly 206 includes eight rotary drive assemblies configuredto couple with and actuate up to a corresponding eight inputs of asurgical instrument (not shown) mounted to the carriage assembly 206.The sterile adapter 208 is configured to mount to the carriage assembly206 by a snap-in interface design that provides for quick release of thesterile adapter 208. The sterile adapter 208 includes eight rotarycouplers that drivingly couple outputs of the eight rotary driveassemblies of the carriage assembly to rotary drive inputs of a surgicalinstrument (not shown) mounted to the carriage assembly 206. In manyembodiments, the eight rotary drive assemblies include six driveassemblies used to actuate up to six rotary drive inputs of a surgicalinstrument and two additional rotary drive assemblies that are used todrive additional rotary drive inputs of advanced surgical instruments(e.g., stapler, vessel sealer).

FIG. 25 shows a drive assembly 212 of the carriage assembly 206. Thedrive assembly 212 includes eight drive assemblies 214. Each of thedrive assemblies 214 includes a drive motor 86, a primary angularorientation sensor 216, a secondary angular orientation sensor 218, anda planetary gear box 220. The eight drive motors 86 of the driveassembly 212 are arranged in a two wide by four deep array. The driveassembly 212 includes a motor housing 222 configured to accommodateand/or support the drive motors 86, the primary angular orientationsensors 216, the secondary angular orientation sensors 218, and theplanetary gear boxes 220.

The drive motors 86 are configured similar to the drive motors 86 of thecarriage assembly 72 discussed herein. As such, the description of thedrive motors 86 of the carriage assembly 72 applies to the drive motors86 of the drive assembly 212 and will therefore not be repeated here.

Any suitable angular orientation sensors can be used for the primary andsecondary angular orientation sensors 216, 218. For example, in manyembodiments, each of the primary angular orientation sensors 216 is anabsolute magnetic encoder that includes a magnetic sensor that tracksthe absolute orientation of a magnet 224 attached to a rotor of thecorresponding drive motor 86. And in many embodiments, the secondaryangular orientation sensors 218 are compact Hall Effects sensors. Theangular orientation the drive motor 86 in each of the drive assemblies214 is redundantly tracked by the primary and secondary angularorientation sensors 216, 218, thereby providing an increased confidencelevel to the tracking of the angular orientation of the drive motor 86.

The eight planetary gear boxes 220 are configured similar to the outputassemblies 88, 90 of the carriage assembly 72 discussed herein. Notabledifferences include that the planetary gear boxes 220 include additionalbearing assemblies distributed along the centerline of the gear box andare thus somewhat longer than the output assemblies 88, 90. The eightplanetary gear boxes 220 are relatively heavy duty, highlyback-drivable, efficient, have low backlash (e.g., 0.05 degree). Twoplanetary stages are used to produce a 28 to 1 gear reduction forstandard low-speed drive assemblies 214 (e.g., seven of the eight driveassemblies 214). And one planetary stage is used to produce a 5.3 to 1gear reduction for a low-speed drive assembly 214 (e.g., one of theeight drive assemblies).

As discussed herein, each of the drive motors 86 includes magnetic fluxshields 172 disposed at the ends of the drive motors 86. The fluxshields 172 serve to entrain magnetic flux lines emanating from themagnetized motor rotor so that those magnetic flux lines do not extendadjacent to the drive motor 86 to interfere with an adjacent drive motorand/or interfere with an adjacent primary and/or secondary angularorientation sensor 216, 218.

Other variations are within the spirit of the present invention. Thus,while the invention is susceptible to various modifications andalternative constructions, certain illustrated embodiments thereof areshown in the drawings and have been described above in detail. It shouldbe understood, however, that there is no intention to limit theinvention to the specific form or forms disclosed, but on the contrary,the intention is to cover all modifications, alternative constructions,and equivalents falling within the spirit and scope of the invention, asdefined in the appended claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. The term “connected” is to beconstrued as partly or wholly contained within, attached to, or joinedtogether, even if there is something intervening. Recitation of rangesof values herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate embodiments of the invention and does not pose a limitationon the scope of the invention unless otherwise claimed. No language inthe specification should be construed as indicating any non-claimedelement as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

What is claimed is:
 1. A robotic assembly configured to support, insert,retract, and actuate a surgical instrument mounted to the roboticassembly, the robotic assembly comprising: an instrument holder basemember; a motor housing moveably mounted to the instrument holder basemember; a carriage drive mechanism operable to selectively translate themotor housing relative to the instrument holder base member along aninsertion axis of the surgical instrument; a plurality of drive motors,each of the drive motors being mounted to the motor housing; a pluralityof gear boxes, each of the gear boxes being drivingly coupled with oneof the drive motors; a plurality of output drive couplings, each of theoutput drive couplings being drivingly coupled with a corresponding oneof the gear boxes, each of the output drive couplings being configuredto drivingly couple with a corresponding input drive coupling of thesurgical instrument; and a sensor assembly that includes an orientationsensor, a sensor target, and a sensor shaft drivingly coupling thesensor target to a corresponding one of the output drive couplingsthrough an aperture in an outer housing of the corresponding gear box;the sensor shaft being driven by an output link of the correspondinggear box that rotates in unison with the corresponding output drivecoupling.
 2. The robotic assembly of claim 1, wherein the orientationsensor optically reads the sensor target.
 3. The robotic assembly ofclaim 1, comprising a plurality of sensor assemblies, each of the sensorassemblies including an orientation sensor, a sensor target, and asensor shaft drivingly coupling the sensor target to a corresponding oneof the output drive couplings through an aperture in an outer housing ofthe corresponding gear box; each sensor shaft being driven by an outputlink of the corresponding gear box that rotates in unison with thecorresponding output drive coupling.
 4. The robotic assembly of claim 1,wherein sensor shaft rotates at a rotation rate in response to rotationof the corresponding output drive coupling at the rotation rate.
 5. Therobotic assembly of claim 1, wherein a gear ratio between at least oneof the motors and the corresponding output drive coupling is less than40:1.
 6. The robotic assembly of claim 1, wherein each of the outputgear boxes have two or fewer gear reduction stages.
 7. The roboticassembly of claim 3, wherein the drive motors are disposed between theorientation sensors and the output drive couplings.
 8. The roboticassembly of claim 7, wherein each of the sensor shafts is drivinglycoupled to the corresponding output drive coupling via a sensor shaftgear that extends through the aperture in the corresponding outerhousing to engage an output gear that rotates in unison with thecorresponding output drive coupling.
 9. The robotic assembly of claim 8,wherein: two of the sensor shaft gears overlap along a shaft directionparallel to rotational axes of the sensor shafts by an overlap distance;and one or more of the corresponding apertures and output gears isconfigured to accommodate the overlap of the sensor shaft gears alongthe shaft direction.
 10. The robotic assembly of claim 1, wherein atleast one of the gear boxes include a planetary gear box that includes ashaft bearing configured to react moment so as to inhibit an axis ofrotation of an inner race of the shaft bearing from becoming misalignedwith an axis of rotation of an outer race of the shaft bearing.
 11. Therobotic assembly of claim 10, wherein the shaft bearing includes tworows of rolling elements.
 12. The robotic assembly of claim 1, whereinat least one of the gear boxes include a planetary gear box thatincludes a carrier gear that has external gear teeth that are engaged bya sensor shaft gear extending through the aperture, the sensor shaftgear being drivingly coupled with the sensor shaft.
 13. A roboticassembly configured to support, insert, retract, and actuate a surgicalinstrument mounted to the robotic assembly, the robotic assemblycomprising: an instrument holder base member; a motor housing moveablymounted to the instrument holder base member; a carriage drive mechanismoperable to selectively translate the motor housing relative to theinstrument holder base member along an insertion axis of the surgicalinstrument; five drive motors, each of the drive motors being mounted tothe motor housing, each of the drive motors including a magnetic fluxshield; five gear boxes, each of the gear boxes being drivingly coupledwith one of the drive motors; five output drive couplings, each of theoutput drive couplings being drivingly coupled with a corresponding oneof the gear boxes, each of the output drive couplings configured to bedrivingly coupled with a corresponding input drive coupling of thesurgical instrument; and five sensor assemblies, each sensor assemblyincluding an orientation sensor and a sensor shaft drivingly couplingthe orientation sensor to a corresponding one of the output couplingsthrough an aperture in an outer housing of the corresponding gear box,the sensor shaft being driven by an output link of the correspondinggear box that rotates in unison with the corresponding output drivecoupling.
 14. The robotic assembly of claim 13, wherein one or more ofthe output drive couplings are constrained to rotate around a rotationaxis substantially parallel to the insertion axis.
 15. The roboticassembly of claim 13, wherein the output drive couplings are arranged ina pattern with four corner output drive couplings and a central outputdrive coupling disposed between the four corner output drive couplings.16. The robotic assembly of claim 13, wherein a maximum of two outputdrive couplings are stacked in a width direction of the motor housing.17. The robotic assembly of claim 13, further comprising a radiofrequency identification (RFID) antenna module designed to read aninstrument RFID tag at a range between 0 mm and approximately 20 mmseparation distance.
 18. The robotic assembly of claim 13, comprising acircuit board including the five orientation sensors of the five sensorassemblies.
 19. The robotic assembly of claim 18, wherein the circuitboard further includes five rotor orientation sensors, each rotororientation sensor being configured to monitor angular orientation of arotor of a corresponding one of the five drive motors.
 20. The roboticassembly of claim 13, wherein: the surgical instrument includes atwo-fingered end effector; each of two of the output drive couplingsthat are furthest away from the insertion axis are used to articulate acorresponding finger of a two-fingered end effector; and the two figurescan be articulated to provide both grip and yaw motions of thetwo-fingered end effector.